Glow plug for an engine



FIG. 1 is a perspective view of a glow plug for an engine, showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a right side elevational view thereof; and,

FIG. 6 is a top plan view thereof, the bottom plan view thereof being hidden and unornamented in use.

The broken lines in the foregoing figures are shown for illustrative purposes only and form no part of the invention in the figures in which they appear. 

The ornamental design for a glow plug for an engine, as shown and described. 